The dreaded check engine light.
Background: 1999 E430 with 56K original miles.
This morning I took it to the MB dealer to have the Tranny fluid and filter replaced this morning. The car runs and shifts beautifully.
At about 1PM while out for an errand, the dreaded light came on. There is no apparant degradation in performance. I took it home and put my OBDII scan tool on it. and it reads PO156 Powertrain HO2S circuit bank 2 sensor 2.
Any ideas on what it might be would be appreciated.
Thanks
Joe
Go back and have them check their work or clear the code and see if it comes back.



